Provide a standardised mechanism to render nested attributes in a PSObject expanded with dependency visualisation. #24471

Summary of the new feature / enhancement

Provide a standardised way to render nested attributes expanded (with Format-Table and Format-List). This would affect any PSObject with nested attributes. However, it would also make a tree.com replacement using Get-ChildItem -Recurse significantly easier to implement.

As an example, consider the undermentioned question that I posed earlier today: ¹

1. #!/usr/bin/env pwsh
   Get-Error

2. Details

   Exception             : 
       Type           : System.Management.Automation.CommandNotFoundException
       ErrorRecord    : 
           Exception             : 
               Type    : System.Management.Automation.ParentContainsErrorRecordException
               Message : The 'Show-Tree' command was found in the module 'Pscx', but the module could not be loaded due to the following error: [Could not load file or assembly 'System.Messaging, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.
                         ]
                         For more information, run 'Import-Module Pscx'.
               HResult : -2146233087
           TargetObject          : Show-Tree
           CategoryInfo          : ObjectNotFound: (Show-Tree:String) [], ParentContainsErrorRecordException
           FullyQualifiedErrorId : CouldNotAutoloadMatchingModule
           InvocationInfo        : 
               ScriptLineNumber : 1
               OffsetInLine     : 1
               HistoryId        : 22
               Line             : Show-Tree
               Statement        : Show-Tree
               PositionMessage  : At line:1 char:1
                                  + Show-Tree
                                  + ~~~~~~~~~
               InvocationName   : Show-Tree
               CommandOrigin    : Internal
           ScriptStackTrace      : at <ScriptBlock>, <No file>: line 1
       CommandName    : Show-Tree
       TargetSite     : 
           Name          : TryModuleAutoDiscovery
           DeclaringType : [System.Management.Automation.CommandDiscovery]
           MemberType    : Method
           Module        : System.Management.Automation.dll
       Message        : The 'Show-Tree' command was found in the module 'Pscx', but the module could not be loaded due to the following error: [Could not load file or assembly 'System.Messaging, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.
                        ]
                        For more information, run 'Import-Module Pscx'.
       Data           : System.Collections.ListDictionaryInternal
       InnerException : 
           Type           : System.Management.Automation.CmdletInvocationException
           ErrorRecord    : 
               Exception             : 
                   Type       : System.IO.FileNotFoundException
                   Message    : Could not load file or assembly 'System.Messaging, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.
                                
                   FileName   : System.Messaging, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
                   TargetSite : 
                       Name          : GetExportedTypes
                       DeclaringType : [System.Reflection.RuntimeAssembly]
                       MemberType    : Method
                       Module        : System.Private.CoreLib.dll
                   Source     : System.Private.CoreLib
                   HResult    : -2147024894
                   StackTrace : 
      at System.Reflection.RuntimeAssembly.GetExportedTypes(QCallAssembly assembly, ObjectHandleOnStack retTypes)
      at System.Reflection.RuntimeAssembly.GetExportedTypes()
      at System.Management.Automation.Runspaces.PSSnapInHelpers.GetAssemblyTypes(Assembly assembly, String name)
      at System.Management.Automation.Runspaces.PSSnapInHelpers.AnalyzeModuleAssemblyWithReflection(Assembly assembly, String name, PSSnapInInfo psSnapInInfo, PSModuleInfo moduleInfo, String helpFile, Dictionary`2& cmdlets, Dictionary`2& aliases, Dictionary`2& providers)
      at System.Management.Automation.Runspaces.PSSnapInHelpers.AnalyzePSSnapInAssembly(Assembly assembly, String name, PSSnapInInfo psSnapInInfo, PSModuleInfo moduleInfo, Dictionary`2& cmdlets, Dictionary`2& aliases, Dictionary`2& providers, String& helpFile)
      at System.Management.Automation.Runspaces.InitialSessionState.ImportCmdletsFromAssembly(Assembly assembly, PSModuleInfo module)
      at Microsoft.PowerShell.Commands.ModuleCmdletBase.LoadBinaryModule(PSModuleInfo parentModule, String moduleName, String fileName, Assembly assemblyToLoad, String moduleBase, SessionState ss, ImportModuleOptions options, ManifestProcessingFlags manifestProcessingFlags, String prefix, Boolean& found, String 
   shortModuleName, Boolean disableFormatUpdates)
      at Microsoft.PowerShell.Commands.ModuleCmdletBase.LoadModule(PSModuleInfo parentModule, String fileName, String moduleBase, String prefix, SessionState ss, Object privateData, ImportModuleOptions& options, ManifestProcessingFlags manifestProcessingFlags, Boolean& found, Boolean& moduleFileFound)
      at Microsoft.PowerShell.Commands.ModuleCmdletBase.LoadModuleNamedInManifest(PSModuleInfo parentModule, ModuleSpecification moduleSpecification, String moduleBase, Boolean searchModulePath, String prefix, SessionState ss, ImportModuleOptions options, ManifestProcessingFlags manifestProcessingFlags, Object 
   privateData, Boolean& found, String shortModuleName, Nullable`1 manifestLanguageMode)
      at Microsoft.PowerShell.Commands.ModuleCmdletBase.LoadModuleManifest(String moduleManifestPath, ExternalScriptInfo manifestScriptInfo, Hashtable data, Hashtable localizedData, ManifestProcessingFlags manifestProcessingFlags, Version minimumVersion, Version maximumVersion, Version requiredVersion, Nullable`1 
   requiredModuleGuid, ImportModuleOptions& options, Boolean& containedErrors)
      at Microsoft.PowerShell.Commands.ModuleCmdletBase.LoadModule(PSModuleInfo parentModule, String fileName, String moduleBase, String prefix, SessionState ss, Object privateData, ImportModuleOptions& options, ManifestProcessingFlags manifestProcessingFlags, Boolean& found, Boolean& moduleFileFound)
      at Microsoft.PowerShell.Commands.ImportModuleCommand.ImportModule_LocallyViaName(ImportModuleOptions importModuleOptions, String name)
      at Microsoft.PowerShell.Commands.ImportModuleCommand.ImportModule_LocallyViaName_WithTelemetry(ImportModuleOptions importModuleOptions, String name)
      at Microsoft.PowerShell.Commands.ImportModuleCommand.ProcessRecord()
      at System.Management.Automation.CommandProcessor.ProcessRecord()
               CategoryInfo          : NotSpecified: (:) [Import-Module], FileNotFoundException
               FullyQualifiedErrorId : System.IO.FileNotFoundException,Microsoft.PowerShell.Commands.ImportModuleCommand
               InvocationInfo        : 
                   MyCommand       : Import-Module
                   HistoryId       : 22
                   InvocationName  : Import-Module
                   CommandOrigin   : Internal
               ScriptStackTrace      : at <ScriptBlock>, <No file>: line 1
               PipelineIterationInfo : 
                                 0
                                 1
           TargetSite     : 
               Name          : Invoke
               DeclaringType : [System.Management.Automation.Runspaces.PipelineBase]
               MemberType    : Method
               Module        : System.Management.Automation.dll
           Message        : Could not load file or assembly 'System.Messaging, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.
                            
           InnerException : 
               Type       : System.IO.FileNotFoundException
               Message    : Could not load file or assembly 'System.Messaging, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.
                            
               FileName   : System.Messaging, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
               TargetSite : 
                   Name          : GetExportedTypes
                   DeclaringType : [System.Reflection.RuntimeAssembly]
                   MemberType    : Method
                   Module        : System.Private.CoreLib.dll
               Source     : System.Private.CoreLib
               HResult    : -2147024894
               StackTrace : 
      at System.Reflection.RuntimeAssembly.GetExportedTypes(QCallAssembly assembly, ObjectHandleOnStack retTypes)
      at System.Reflection.RuntimeAssembly.GetExportedTypes()
      at System.Management.Automation.Runspaces.PSSnapInHelpers.GetAssemblyTypes(Assembly assembly, String name)
      at System.Management.Automation.Runspaces.PSSnapInHelpers.AnalyzeModuleAssemblyWithReflection(Assembly assembly, String name, PSSnapInInfo psSnapInInfo, PSModuleInfo moduleInfo, String helpFile, Dictionary`2& cmdlets, Dictionary`2& aliases, Dictionary`2& providers)
      at System.Management.Automation.Runspaces.PSSnapInHelpers.AnalyzePSSnapInAssembly(Assembly assembly, String name, PSSnapInInfo psSnapInInfo, PSModuleInfo moduleInfo, Dictionary`2& cmdlets, Dictionary`2& aliases, Dictionary`2& providers, String& helpFile)
      at System.Management.Automation.Runspaces.InitialSessionState.ImportCmdletsFromAssembly(Assembly assembly, PSModuleInfo module)
      at Microsoft.PowerShell.Commands.ModuleCmdletBase.LoadBinaryModule(PSModuleInfo parentModule, String moduleName, String fileName, Assembly assemblyToLoad, String moduleBase, SessionState ss, ImportModuleOptions options, ManifestProcessingFlags manifestProcessingFlags, String prefix, Boolean& found, String 
   shortModuleName, Boolean disableFormatUpdates)
      at Microsoft.PowerShell.Commands.ModuleCmdletBase.LoadModule(PSModuleInfo parentModule, String fileName, String moduleBase, String prefix, SessionState ss, Object privateData, ImportModuleOptions& options, ManifestProcessingFlags manifestProcessingFlags, Boolean& found, Boolean& moduleFileFound)
      at Microsoft.PowerShell.Commands.ModuleCmdletBase.LoadModuleNamedInManifest(PSModuleInfo parentModule, ModuleSpecification moduleSpecification, String moduleBase, Boolean searchModulePath, String prefix, SessionState ss, ImportModuleOptions options, ManifestProcessingFlags manifestProcessingFlags, Object 
   privateData, Boolean& found, String shortModuleName, Nullable`1 manifestLanguageMode)
      at Microsoft.PowerShell.Commands.ModuleCmdletBase.LoadModuleManifest(String moduleManifestPath, ExternalScriptInfo manifestScriptInfo, Hashtable data, Hashtable localizedData, ManifestProcessingFlags manifestProcessingFlags, Version minimumVersion, Version maximumVersion, Version requiredVersion, Nullable`1 
   requiredModuleGuid, ImportModuleOptions& options, Boolean& containedErrors)
      at Microsoft.PowerShell.Commands.ModuleCmdletBase.LoadModule(PSModuleInfo parentModule, String fileName, String moduleBase, String prefix, SessionState ss, Object privateData, ImportModuleOptions& options, ManifestProcessingFlags manifestProcessingFlags, Boolean& found, Boolean& moduleFileFound)
      at Microsoft.PowerShell.Commands.ImportModuleCommand.ImportModule_LocallyViaName(ImportModuleOptions importModuleOptions, String name)
      at Microsoft.PowerShell.Commands.ImportModuleCommand.ImportModule_LocallyViaName_WithTelemetry(ImportModuleOptions importModuleOptions, String name)
      at Microsoft.PowerShell.Commands.ImportModuleCommand.ProcessRecord()
      at System.Management.Automation.CommandProcessor.ProcessRecord()
           Source         : System.Management.Automation
           HResult        : -2146233087
           StackTrace     : 
      at System.Management.Automation.Runspaces.PipelineBase.Invoke(IEnumerable input)
      at System.Management.Automation.PowerShell.Worker.ConstructPipelineAndDoWork(Runspace rs, Boolean performSyncInvoke)
      at System.Management.Automation.PowerShell.CoreInvokeHelper[TInput,TOutput](PSDataCollection`1 input, PSDataCollection`1 output, PSInvocationSettings settings)
      at System.Management.Automation.PowerShell.CoreInvoke[TInput,TOutput](PSDataCollection`1 input, PSDataCollection`1 output, PSInvocationSettings settings)
      at System.Management.Automation.PowerShell.Invoke[T]()
      at System.Management.Automation.CommandDiscovery.AutoloadSpecifiedModule(String moduleName, ExecutionContext context, SessionStateEntryVisibility visibility, Exception& exception)
       Source         : System.Management.Automation
       HResult        : -2146233087
       StackTrace     : 
      at System.Management.Automation.CommandDiscovery.TryModuleAutoDiscovery(String commandName, ExecutionContext context, String originalCommandName, CommandOrigin commandOrigin, SearchResolutionOptions searchResolutionOptions, CommandTypes commandTypes, Exception& lastError)
      at System.Management.Automation.CommandDiscovery.LookupCommandInfo(String commandName, CommandTypes commandTypes, SearchResolutionOptions searchResolutionOptions, CommandOrigin commandOrigin, ExecutionContext context)
      at System.Management.Automation.PipelineOps.AddCommand(PipelineProcessor pipe, CommandParameterInternal[] commandElements, CommandBaseAst commandBaseAst, CommandRedirection[] redirections, ExecutionContext context)
      at System.Management.Automation.PipelineOps.InvokePipeline(Object input, Boolean ignoreInput, CommandParameterInternal[][] pipeElements, CommandBaseAst[] pipeElementAsts, CommandRedirection[][] commandRedirections, FunctionContext funcContext)
      at System.Management.Automation.Interpreter.ActionCallInstruction`6.Run(InterpretedFrame frame)
      at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
   TargetObject          : Show-Tree
   CategoryInfo          : ObjectNotFound: (Show-Tree:String) [], CommandNotFoundException
   FullyQualifiedErrorId : CouldNotAutoloadMatchingModule
   InvocationInfo        : 
       ScriptLineNumber : 1
       OffsetInLine     : 1
       HistoryId        : 22
       Line             : Show-Tree
       Statement        : Show-Tree
       PositionMessage  : At line:1 char:1
                          + Show-Tree
                          + ~~~~~~~~~
       InvocationName   : Show-Tree
       CommandOrigin    : Internal
   ScriptStackTrace      : at <ScriptBlock>, <No file>: line 1

Specifically, the undermentioned section:

FileName   : System.Messaging, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
TargetSite : 
    Name          : GetExportedTypes
    DeclaringType : [System.Reflection.RuntimeAssembly]
    MemberType    : Method
    Module        : System.Private.CoreLib.dll

Summarily, how can I replicate TargetSite printing its properties with their values, with indentation to visualise the depedency? I ask because I've been utterly unable to locate online and alone how to force a PSObject with nested properties to render them in the CLI as a tree like Get-Error is evidently able to.

Meta

Originally asked at Reddit, but it was immediately redacted by AutoMod.

I request this because I utilize hash-tables extensively, and visualising one's data in its entirety without performing $HashTable | ConvertTo-YAML isn't possible.

Proposed technical implementation details (optional)

As its (currently sole) response states:

There's no single/automatic way of doing this unfortunately. The Get-Error cmdlet works by inserting the System.Management.Automation.ErrorRecord#PSExtendedError type name to the error object and PowerShell has a custom formatter set for that type name to do the manual string building to create this format [in the undermentioned]:

PowerShell/src/System.Management.Automation/FormatAndOutput/DefaultFormatters/PowerShellCore_format_ps1xml.cs

Lines 824 to 1030 in 623c451

	private static IEnumerable<FormatViewDefinition> ViewsOf_System_Management_Automation_GetError()
	{
	yield return new FormatViewDefinition("GetErrorInstance",
	CustomControl.Create()
	.GroupByProperty("PSErrorIndex", label: "ErrorIndex")
	.StartEntry()
	.AddScriptBlockExpressionBinding(@"
	Set-StrictMode -Off
	$maxDepth = 10
	$ellipsis = ""`u{2026}""
	$resetColor = ''
	$errorColor = ''
	$accentColor = ''
	if ($Host.UI.SupportsVirtualTerminal -and ([string]::IsNullOrEmpty($env:__SuppressAnsiEscapeSequences))) {
	$resetColor = $PSStyle.Reset
	$errorColor = $psstyle.Formatting.Error
	$accentColor = $PSStyle.Formatting.FormatAccent
	}
	function Show-ErrorRecord($obj, [int]$indent = 0, [int]$depth = 1) {
	$newline = [Environment]::Newline
	$output = [System.Text.StringBuilder]::new()
	$prefix = ' ' * $indent
	$expandTypes = @(
	'Microsoft.Rest.HttpRequestMessageWrapper'
	'Microsoft.Rest.HttpResponseMessageWrapper'
	'System.Management.Automation.InvocationInfo'
	)
	# if object is an Exception, add an ExceptionType property
	if ($obj -is [Exception]) {
	$obj | Add-Member -NotePropertyName Type -NotePropertyValue $obj.GetType().FullName -ErrorAction Ignore
	}
	# first find the longest property so we can indent properly
	$propLength = 0
	foreach ($prop in $obj.PSObject.Properties) {
	if ($prop.Value -ne $null -and $prop.Value -ne [string]::Empty -and $prop.Name.Length -gt $propLength) {
	$propLength = $prop.Name.Length
	}
	}
	$addedProperty = $false
	foreach ($prop in $obj.PSObject.Properties) {
	# don't show empty properties or our added property for $error[index]
	if ($prop.Value -ne $null -and $prop.Value -ne [string]::Empty -and $prop.Value.count -gt 0 -and $prop.Name -ne 'PSErrorIndex') {
	$addedProperty = $true
	$null = $output.Append($prefix)
	$null = $output.Append($accentColor)
	$null = $output.Append($prop.Name)
	$propNameIndent = ' ' * ($propLength - $prop.Name.Length)
	$null = $output.Append($propNameIndent)
	$null = $output.Append(' : ')
	$null = $output.Append($resetColor)
	$newIndent = $indent + 4
	# only show nested objects that are Exceptions, ErrorRecords, or types defined in $expandTypes and types not in $ignoreTypes
	if ($prop.Value -is [Exception] -or $prop.Value -is [System.Management.Automation.ErrorRecord] -or
	$expandTypes -contains $prop.TypeNameOfValue -or ($prop.TypeNames -ne $null -and $expandTypes -contains $prop.TypeNames[0])) {
	if ($depth -ge $maxDepth) {
	$null = $output.Append($ellipsis)
	}
	else {
	$null = $output.Append($newline)
	$null = $output.Append((Show-ErrorRecord $prop.Value $newIndent ($depth + 1)))
	}
	}
	# `TargetSite` has many members that are not useful visually, so we have a reduced view of the relevant members
	elseif ($prop.Name -eq 'TargetSite' -and $prop.Value.GetType().Name -eq 'RuntimeMethodInfo') {
	if ($depth -ge $maxDepth) {
	$null = $output.Append($ellipsis)
	}
	else {
	$targetSite = [PSCustomObject]@{
	Name = $prop.Value.Name
	DeclaringType = $prop.Value.DeclaringType
	MemberType = $prop.Value.MemberType
	Module = $prop.Value.Module
	}
	$null = $output.Append($newline)
	$null = $output.Append((Show-ErrorRecord $targetSite $newIndent ($depth + 1)))
	}
	}
	# `StackTrace` is handled specifically because the lines are typically long but necessary so they are left justified without additional indentation
	elseif ($prop.Name -eq 'StackTrace') {
	# for a stacktrace which is usually quite wide with info, we left justify it
	$null = $output.Append($newline)
	$null = $output.Append($prop.Value)
	}
	# Dictionary and Hashtable we want to show as Key/Value pairs, we don't do the extra whitespace alignment here
	elseif ($prop.Value -is [System.Collections.IDictionary]) {
	$isFirstElement = $true
	foreach ($key in ($prop.Value.Keys | Sort-Object)) {
	if ($isFirstElement) {
	$null = $output.Append($newline)
	}
	if ($key -eq 'Authorization') {
	$null = $output.Append(""${prefix} ${accentColor}${key} : ${resetColor}${ellipsis}${newline}"")
	}
	else {
	$null = $output.Append(""${prefix} ${accentColor}${key} : ${resetColor}$($prop.Value[$key])${newline}"")
	}
	$isFirstElement = $false
	}
	}
	# if the object implements IEnumerable and not a string, we try to show each object
	# We ignore the `Data` property as it can contain lots of type information by the interpreter that isn't useful here
	elseif (!($prop.Value -is [System.String]) -and $prop.Value.GetType().GetInterface('IEnumerable') -ne $null -and $prop.Name -ne 'Data') {
	if ($depth -ge $maxDepth) {
	$null = $output.Append($ellipsis)
	}
	else {
	$isFirstElement = $true
	foreach ($value in $prop.Value) {
	$null = $output.Append($newline)
	$valueIndent = ' ' * ($newIndent + 2)
	if ($value -is [Type]) {
	# Just show the typename instead of it as an object
	$null = $output.Append(""${prefix}${valueIndent}[$($value.ToString())]"")
	}
	elseif ($value -is [string] -or $value.GetType().IsPrimitive) {
	$null = $output.Append(""${prefix}${valueIndent}${value}"")
	}
	else {
	if (!$isFirstElement) {
	$null = $output.Append($newline)
	}
	$null = $output.Append((Show-ErrorRecord $value $newIndent ($depth + 1)))
	}
	$isFirstElement = $false
	}
	}
	}
	elseif ($prop.Value -is [Type]) {
	# Just show the typename instead of it as an object
	$null = $output.Append(""[$($prop.Value.ToString())]"")
	}
	# Anything else, we convert to string.
	# ToString() can throw so we use LanguagePrimitives.TryConvertTo() to hide a convert error
	else {
	$value = $null
	if ([System.Management.Automation.LanguagePrimitives]::TryConvertTo($prop.Value, [string], [ref]$value) -and $value -ne $null)
	{
	if ($prop.Name -eq 'PositionMessage') {
	$value = $value.Insert($value.IndexOf('~'), $errorColor)
	}
	elseif ($prop.Name -eq 'Message') {
	$value = $errorColor + $value
	}
	$isFirstLine = $true
	if ($value.Contains($newline)) {
	# the 3 is to account for ' : '
	$valueIndent = ' ' * ($propLength + 3)
	# need to trim any extra whitespace already in the text
	foreach ($line in $value.Split($newline)) {
	if (!$isFirstLine) {
	$null = $output.Append(""${newline}${prefix}${valueIndent}"")
	}
	$null = $output.Append($line.Trim())
	$isFirstLine = $false
	}
	}
	else {
	$null = $output.Append($value)
	}
	}
	}
	$null = $output.Append($newline)
	}
	}
	# if we had added nested properties, we need to remove the last newline
	if ($addedProperty) {
	$null = $output.Remove($output.Length - $newline.Length, $newline.Length)
	}
	$output.ToString()
	}
	# Add back original typename and remove PSExtendedError
	if ($_.PSObject.TypeNames.Contains('System.Management.Automation.ErrorRecord#PSExtendedError')) {
	$_.PSObject.TypeNames.Add('System.Management.Automation.ErrorRecord')
	$null = $_.PSObject.TypeNames.Remove('System.Management.Automation.ErrorRecord#PSExtendedError')
	}
	elseif ($_.PSObject.TypeNames.Contains('System.Exception#PSExtendedError')) {
	$_.PSObject.TypeNames.Add('System.Exception')
	$null = $_.PSObject.TypeNames.Remove('System.Exception#PSExtendedError')
	}
	Show-ErrorRecord $_
	")
	.EndEntry()
	.EndControl());
	}

You can certainly copy/modify the code for your own needs but it's not a simple function you can call here and something very specific to the Get-Error output. You could look at using a YAML library to try and achieve a similar setup but it won't strictly be the same as the Get-Error format which is YAML like but not actually YAML.